scholarly journals Numerical study of splay faults in subduction zones: The effects of bimaterial interface and free surface

2011 ◽  
Vol 116 (B10) ◽  
Author(s):  
Shintaro Tamura ◽  
Satoshi Ide
Keyword(s):  
Free Surface ◽  
Subduction Zones ◽  
Numerical Study ◽  
Bimaterial Interface ◽  
Splay Faults

Sloshing in Rectangular and Cylindrical Tanks

2002 ◽  
Vol 46 (03) ◽  
pp. 186-200 ◽  
Author(s):  
Pierre C. Sames ◽  
Delphine Marcouly ◽  
Thomas E. Schellin
Keyword(s):  
Free Surface ◽  
Finite Volume ◽  
Temporal Evolution ◽  
Numerical Study ◽  
Computational Method ◽  
Test Cases ◽  
Grid Refinement ◽  
Cylindrical Tank ◽  
Excitation Period ◽  
Cylindrical Tanks

To validate an existing finite volume computational method, featuring a novel scheme to capture the temporal evolution of the free surface, fluid motions in partially filled tanks were simulated. The purpose was to compare computational and experimental results for test cases where measurements were available. Investigations comprised sloshing in a rectangular tank with a baffle at 60% filling level and in a cylindrical tank at 50% filling level. The numerical study started with examining effects of systematic grid refinement and concluded with examining effects of three-dimensionality and effects of variation of excitation period and amplitude. Predicted time traces of pressures and forces compared favorably with measurements.

scholarly journals Graphene-Based One-Dimensional Terahertz Phononic Crystal: Band Structures and Surface Modes

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2205
Author(s):  
Ilyasse Quotane ◽  
El Houssaine El Boudouti ◽  
Bahram Djafari-Rouhani
Keyword(s):  
Free Surface ◽  
Sagittal Plane ◽  
Numerical Study ◽  
Phononic Crystal ◽  
Acoustic Properties ◽  
Band Structures ◽  
Surface Modes ◽  
Acoustic Modes ◽  
And Behavior ◽  
The Waves

In this paper, we provide a theoretical and numerical study of the acoustic properties of infinite and semi-infinite superlattices made out of graphene-semiconductor bilayers. In addition to the band structure, we emphasize the existence and behavior of localized and resonant acoustic modes associated with the free surface of such structures. These modes are polarized in the sagittal plane, defined by the incident wavevector and the normal to the layers. The surface modes are obtained from the peaks of the density of states, either inside the bulk bands or inside the minigaps of the superlattice. In these structures, the two directions of vibrations (longitudinal and transverse) are coupled giving rise to two bulk bands associated with the two polarizations of the waves. The creation of the free surface of the superlattice induces true surface localized modes inside the terahertz acoustic forbidden gaps, but also pseudo-surface modes which appear as well-defined resonances inside the allowed bands of the superlattice. Despite the low thickness of the graphene layer, and though graphene is a gapless material, when it is inserted periodically in a semiconductor, it allows the opening of wide gaps for all values of the wave vector k// (parallel to the interfaces). Numerical illustrations of the band structures and surface modes are given for graphene-Si superlattices, and the surface layer can be either Si or graphene. These surface acoustic modes can be used to realize liquid or bio-sensors graphene-based phononic crystal operating in the THz frequency domain.

Numerical Simulation of Breaking Waves Using a Level Set Method

2002 ◽  
Author(s):  
Pablo Go´mez ◽  
Julio Herna´ndez ◽  
Joaqui´n Lo´pez ◽  
Fe´lix Faura
Keyword(s):  
Free Surface ◽  
Level Set Method ◽  
Level Set ◽  
Stokes Equations ◽  
Numerical Study ◽  
Operating Conditions ◽  
Breaking Wave ◽  
Level Set Function ◽  
Set Function ◽  
The Impact

A numerical study of the initial stages of wave breaking processes in shallow water is presented. The waves considered are assumed to be generated by moving a piston in a two-dimensional channel, and may appear, for example, in the injection chamber of a high-pressure die casting machine under operating conditions far from the optimal. A numerical model based on a finite-difference discretization of the Navier-Stokes equations in a Cartesian grid and a second-order approximate projection method has been developed and used to carry out the simulations. The evolution of the free surface is described using a level set method, with a reinitialization procedure of the level set function which uses a local grid refinement near the free surface. The ability of different algorithms to improve mass conservation in the reinitialization step of the level set function has been tested in a time-reversed single vortex flow. The results for the breaking wave profiles show the flow characteristics after the impact of the first plunging jet onto the wave’s forward face and during the subsequent splash-up.

A Numerical Study of Electrode Arrangements for Precise Microdrop Generation in an Electrowetting-Based Digital Microfluidic Platform

2019 ◽  
Author(s):  
Yin Guan ◽  
Baiyun Li ◽  
Mengnan Zhu ◽  
Shengjie Cheng ◽  
Jiyue Tu ◽  
...  
Keyword(s):  
Free Surface ◽  
Cell Model ◽  
Numerical Study ◽  
Digital Microfluidics ◽  
Surface Force ◽  
Viscous Force ◽  
Generation Process ◽  
Parallel Plates ◽  
Digital Microfluidic ◽  
The Impact

Abstract Owing to the wide applications in a large variety of multi-disciplinary areas, electrowetting-based digital microfluidics (DMF) has received considerable attention in the last decade. However, because of the complexity involved in the droplet generation process, the techniques and configurations for precise and controllable microdrop generation are still unclear. In this paper, a numerical study has been performed to investigate the impact of electrode arrangements on microdrop generation in an electrowetting-based DMF Platform proposed by a previously published experimental work. The governing equations for the microfluidic flow are solved by a finite volume formulation with a two-step projection method on a fixed numerical domain. The free surface of the microdrop is tracked by a coupled level-set and volume-of-fluid (CLSVOF) method, and the surface tension at the free surface is computed by the continuum surface force (CSF) scheme. A simplified viscous force scheme based on the ‘Hele-Shaw cell’ model is adopted to evaluate the viscous force exerted by the parallel plates. The generation process has been simulated with three different electrode arrangements, namely, ‘SL’, ‘SW’, and ‘SQ’. The effect of electrode arrangement on microdrop volume has been investigated. Besides, the influences of the initial microdrop location and volume on the generation process for the ‘SL’ design have been studied. The results can be used to advance microdrop generation techniques for various electrowetting-based DMF applications.

scholarly journals An Experimental and Numerical Study of the Free Surface in an Uphill Teeming Ingot Casting Process

2020 ◽  
Vol 91 (6) ◽  
pp. 1900609
Author(s):  
Jun Yin ◽  
Shuo Guo ◽  
Mikael Ersson ◽  
Pär G. Jönsson
Keyword(s):  
Free Surface ◽  
Numerical Study ◽  
Casting Process ◽  
Ingot Casting

MELTING ABOUT A HEATED CYLINDER IN AN ICE-FILLED SQUARE ENCLOSURE WITH AN ISOTHERMALS FREE SURFACE

1999 ◽  
Vol 23 (3-4) ◽  
pp. 409-423
Author(s):  
P.H. Oosthuizen ◽  
J.T. Paul
Keyword(s):  
Free Surface ◽  
Numerical Study ◽  
Experimental Studies ◽  
Freezing Temperature ◽  
Lower Surface ◽  
Uniform Temperature ◽  
Square Enclosure ◽  
Heated Cylinder ◽  
Finite Element Procedure ◽  
Side Walls

A numerical study of the flow about and heat transfer from a heated cylinder centrally positioned in a square enclosure containing ice has been undertaken. The cylinder is heated to a uniform temperature that is higher than the freezing temperature of water and melting, therefore, occurs in the vicinity of the cylinder. The two side-walls of the enclosure are kept at a uniform temperature that is below the freezing temperature. The conditions considered here are such that there can be significant natural convection in the water near the cylinder. The lower surface of the enclosure is assumed to be adiabatic. The liquid has a free surface which is assumed to be flat. In most previous numerical studies of such a situation it has been assumed that the free surface is adiabatic. In experimental studies of the is type of flow, however, the free surface is often effectively cooled. In order to evaluate the effect of this, it has here been assumed that the free surface is at the uniform temperature that is below the freezing temperature but that is, in general, higher than that of the cooled side-walls. The governing equations have been expressed in dimensionless form and solved using a finite element procedure. The effect of the various governing parameters on the mean cylinder Nusselt number and on the thickness of the melted region about the cylinder have mainly been considered. The effect of the assumed free-surface temperature has, in particular, been studied.

scholarly journals Experimental and Numerical Study of Free-Surface Flows in a Corrugated Pipe

Water ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 638 ◽  
Author(s):  
Francesco Calomino ◽  
Giancarlo Alfonsi ◽  
Roberto Gaudio ◽  
Antonino D’Ippolito ◽  
Agostino Lauria ◽  
...  
Keyword(s):  
Free Surface ◽  
Numerical Study ◽  
Free Surface Flows ◽  
Surface Flows

Numerical Study of Pressure Wave Transmission in Liquid Under Different Interface Conditions Using Particle Method

2009 ◽  
Author(s):  
Zhongguo Sun ◽  
Guang Xi
Keyword(s):  
Free Surface ◽  
Pressure Wave ◽  
Numerical Study ◽  
Wave Length ◽  
Particle Method ◽  
Wave Transmission ◽  
Wave Transport ◽  
Moving Particle ◽  
Energy Absorbing ◽  
The Waves

The process of pressure wave transmission in liquid is simulated with the moving particle semi-implicit (MPS) method. The simulation is carried out in a tube full filled with an energy absorbing liquid. Here we studied the shapes and positions of pressure waves and investigated the behavior of the waves under different viscosities and densities of liquids. Some typical parameters of pressure wave, such as peak pressure value, wave length and transport speed are studied. Varying viscosity does not change the wave length and speed of the pressure wave evidently. The effect of interfaces which formed by viscosity difference or density difference is investigated. Reflection is found not always happened on such interfaces. Pressure wave transport to liquid-solid interface and free surface are also simulated. Pressure wave is vanished when closing to free surface. These results give useful qualitative suggestions on controlling the pressure wave in fluid engineering.

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